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From: Nathan Lynch <ntl@pobox.com>
To: Christoph Hellwig <hch@infradead.org>,
	Hoang-Nam Nguyen <hnguyen@linux.vnet.ibm.com>,
	Roland Dreier <rdreier@cisco.com>,
	linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org,
	openfabrics-ewg@openib.org, openib-general@openib.org,
	raisch@de.ibm.com
Subject: Re: [PATCH/RFC 2.6.21 3/5] ehca: completion queue: remove use of do_mmap()
Date: Thu, 11 Jan 2007 13:40:54 -0600	[thread overview]
Message-ID: <20070111194054.GA11770@localdomain> (raw)
In-Reply-To: <20070111192056.GB24623@infradead.org>

Christoph Hellwig wrote:
> On Thu, Jan 11, 2007 at 08:08:36PM +0100, Hoang-Nam Nguyen wrote:
> 
> >  	spin_lock_irqsave(&ehca_cq_idr_lock, flags);
> >  	while (my_cq->nr_callbacks)
> >  		yield();
> 
> Calling yield is a very bad idea in general.  You should probably
> add a waitqueue that gets woken when nr_callbacks reaches zero to
> sleep effectively here.

Isn't that code outright buggy?  Calling into the scheduler with a
spinlock held and local interrupts disabled...


  reply	other threads:[~2007-01-11 19:41 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-01-11 19:08 Hoang-Nam Nguyen
2007-01-11 19:20 ` Christoph Hellwig
2007-01-11 19:40   ` Nathan Lynch [this message]
2007-01-11 19:43     ` Christoph Hellwig
2007-01-11 19:56     ` Roland Dreier
2007-01-12 15:23       ` Hoang-Nam Nguyen
2007-01-12 15:36   ` Hoang-Nam Nguyen

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